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Vulnerability · Published Jul 7, 2026 · Assigned by GitHub_M

CVE-2026-55428Coder: Route hijacking through lack of validation of agent-supplied AllowedIPs in tailnet coordinator

High 8.2

In plain English

A high-severity incorrect authorization in coder from coder. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.2High
Exploit odds (30 days)0.4%top 65.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

Coder allows organizations to provision remote development environments via Terraform. Prior to versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2, the tailnet coordinator validates that an agent's `Addresses` derive from its authenticated UUID but applies no equivalent check to `AllowedIPs`. The coordinator forwards agent-supplied `AllowedIPs` verbatim to tunnel peers which install them into the WireGuard peer configuration. The fix in versions 2.29.7, 2.32.7, 2.33.8, and 2.34.2 validates each `AllowedIPs` prefix against the authenticating agent's UUID just like `Addresses`. As a workaround, monitor coordinator logs for agents advertising unexpected `AllowedIPs` prefixes.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Gogithub.com/coder/coderno fix listedGO-2026-5915
Gogithub.com/coder/coder/v22.34.2GHSA-wrq8-fcv5-8hvp
Gogithub.com/coder/coder/v22.33.8GHSA-wrq8-fcv5-8hvp
Gogithub.com/coder/coder/v22.32.7GHSA-wrq8-fcv5-8hvp
Gogithub.com/coder/coder/v22.29.17GHSA-wrq8-fcv5-8hvp
Gogithub.com/coder/coder/v22.29.17, 2.32.7, 2.33.8, 2.34.2GO-2026-5915

Affected products (as reported)

VendorProductVersions
coder coder >= 2.34.0, < 2.34.2>= 2.33.0, < 2.33.8>= 2.30.0, < 2.32.7< 2.29.17

Weakness: CWE-285, CWE-863 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

References